Diffusers for air conditioning, ventilation and heating systems display a number of characteristics. They should be easily constructed, generate a dispersed air pattern, be quiet, and be easily installed in a ceiling by simple connection to the ducted work. The primary purpose of the diffusers is for air distribution, and a 360.degree. air pattern is usually desirable. In constructing diffusers, they should be generally airtight on the sides so that no air is lost in the ceiling. Lightweight construction saves material and allows for ease of installation.
A number of attempts have been made to improve one or more of these aspects. One problem that has occurred is in the construction of a 360.degree. deflector. Preferably, it will be extremely inexpensive to manufacture, and it either must attach to the sides of the diffuser or attach to a perforated bottom wall that is attached to the sidewalls. If it is attached to a bottom wall, vibration between the deflector and the bottom wall may be a problem. It is therefore an object of the present invention to provide and to disclose a deflector that overcomes these problems by using resilient spacers between the bottom wall and the deflector to prevent vibrations from being transmitted to the bottom wall. These spacers also improve the air distribution by providing a small space between the deflector and the bottom wall uncovering perforations.
The top of the diffuser is connected to the ducting. The top wall in prior art diffusers was usually metal, and each would have to be purchased with the correct opening for the duct. If not, the installer would have to use metal cutting tools to widen the opening to accommodate ducting of different diameters. Metal, moreover, is heavy. One of the objects, therefore, of the present invention is to provide a top wall of lighter weight material which can be cut on site. The present invention uses molded fiberglass, which is also a good thermal and sound insulator. To prevent particles of the fiberglass from being removed during installation and also to minimize the contact with the fiberglass by the installer, the fiberglass may be covered with foil. Foil also makes an excellent surface for printing locating indicia for locating the opening for connection to the ducting. It is an object of the present invention to disclose and provide a diffuser having these properties and solving the problems.
Another problem in air diffusers is to minimize construction costs. Thin sheet metal is lightweight and can be easily formed using low cost hand tools such as tin snips and riveters. One of the objects of the present invention is to disclose and provide an air diffuser of low cost construction, but which when constructed secures the fiberglass top wall within the diffuser so that it will not be dislodged in cutting an opening for insertion of the ducting.
Diffusers having perforated bottom walls offer certain advantages over other types of diffusers for certain application. The air stream is broken into many small streams such that these smaller streams mix well with the room air as shortly after passing through the diffuser. Larger volumes of air can be exchanged without drafts. A perforated screen with a free area of about 51% has been found to be rigid with sufficient free area to pass air without an objectionable pressure drop. Ohe of the objects of the invention is to disclose and provide a diffuser that utilizes the perforated bottom with a radial deflector and that also has the simplified construction of the present invention.
Because of the uncomplicated construction of the deflector, the angles may be changed during construction or even in the field and it is an object of the present invention to disclose and provide for this feature. This feature may be important to modify the air patterns. For example, in rooms with high ceilings, it may be desirable to have a tighter distribution pattern so that a flow of air will reach closer to the ground. An angle change may modify this result.
Improved air distribution can also be accomplished using a perforated deflector that further breaks up the main air stream, and it is an object to disclose and provide such a deflector.
A further object is to disclose and provide a sturdy unit of lightweight construction. The present diffuser has a member of molded fiberglass. Although molded fiberglass has been used previously, it was not protected such that it could be easily damaged during shipping and installation. The useful fiberglass is protected in the present invention and the unit is extremely sturdy yet lightweight.
The present invention meets the previously stated objects, and it also meets other objects that, although not specifically listed as objects, are evident from the description of the invention.